The Good, the Bad & Ugly of More Megapixels

I have often been asked about the Megapixel debate, is it some urban legend? Folklore? Or some old wives tale perpetuated by camera manufacturers? But what I am going to say is going to be based on facts, and having worked with Sony's DSLR division, I sort of know the good and bad of the megapixel race.
All too often, we find ourselves confronted with decisions on which camera is better based on just the megapixel count of a sensor. Now more megapixel means more detail in a picture but only if it is exposed well. Put that context into a low light scene, the sensor's sensitivity comes into play and this negates any gain in detail. But let's not work on that. Let's assess what more megapixels will do for you.

The Good side of More Megapixels

Henri Cartier Bresson of Magnum, known fondly as HCB, didn't like his photos cropped but with more megapixels, cropping is actually good. Let's use a photo I took as an example. The original is above.
Let's do a HCB time lapse into the world of B/W photography and turn this into a contrasty picture of a street scene.

The composition isn't spot on. There is lot of room and in the editorial
room, it would be considered a "loose" photo since it is not tightly
composed.

Here is the cropped photo, by throwing away rougly 1/3 of the size of
the photo, it becomes a better picture.
So if you happen to be shooting with a 24 megapixel DSLR, this image
would be roughly 24MB in RAW size and after cropping, a third of frame,
you are still left with 18MB of image data. Now that is a big image!

The BAD of having More Megapixels

High density sensors cost more to manufacturer and low light handling isn't as good.
Often, dynamic range will suffer as these smaller high density sensors just doesn't have the muscles compete unless helped along with brute force noise reduction steroids. Larger sensors handle light better but large high density sensor cameras also cost a bomb to own.

The UGLY side of More Megapixels

If you look at the above cropped pictures, and realize that you can take a "loose" picture and still rescue it later with cropping, don't you think that you'd be a loose photographer than a tight one?
Pros everywhere have one strong point, they don't need any image cropping for it to come out right. Should you rely on more megapixels to save your day, then you will forever be dependent on it. By relying on post production miracles, you'd stop being a photographer and more of an image manipulator.
This is the ugly side of photography which we all try to avoid but get sucked into. Cropping your image in-camera is the best way to go if you want to improve your sense of composition.

Conclusions

There is no right or wrong way to see this Megapixel Myth. The more insecure you are about your pictures, then the obvious route to take is to have more megapixels. The more confident you are about your photography, then the megapixel myth would have fallen away from you mind and in essence make you an even better photographer. So learn to work with what you have.